Multiple magnetism-controlled topological states in EuAgAs

The interplay between magnetism and band topology is a focus of current research on magnetic topological systems. Based first-principle calculations symmetry analysis, we reveal multiple intriguing states can be realized in single system EuAgAs, controlled by the ordering. material Dirac semimetal paramagnetic state, with pair accidental points. Under different configurations, points evolve into triply-degenerate points, linear double Weyl or being gapped out making mirror characterized Chern numbers. change bulk also manifested surface states, including Fermi arcs cones. In addition, antiferromagnetic feature nontrivial Z4 index, implying higher order topology. These results deepen our understanding provide new perspectives for spintronic applications.